However, as orexinergic neuron activity supports active wake during the diurnal activity cycle36 and preclinical studies in rodents suggest that the orexin-2 receptor (OX2R) is responsible for anti-arousal effects of OXR antagonism37,38, the current study aims to gather more clinical evidence for the effect of an OX2R antagonist in MDD patients. This evidence concerns the gene HCRTR2 and major depressive disorder.